1. Field of the Invention
The present disclosure relates to a field effect transistor and more particularly, to a field effect transistor to be used in a high-frequency amplifier.
2. Description of the Related Art
A nitride semiconductor such as GaN or AlGaN is known as a material for a field effect transistor (FET). The field effect transistor made of the nitride semiconductor is widely used in a power amplifier at microwave band.
In order to obtain a power amplifier having high gain and high output power characteristics, it is important to enhance linearity of the field effect transistor.
As a technique to enhance the linearity of the field effect transistor, there is an example in which at least two transistors each having a different gate recess depth are used, as disclosed in Japanese Translation of PCT Publication No. 2010-539691.